1. Field of the Invention
The present invention relates to processes related to the manufacture of orthotic products using textile braiding techniques, with aerospace quality fibers, resins, and inserts to produce lighter weight, stronger, lower cost, and better fitting orthotic products on standard braiding equipment modified with attachment of special support structures to aid manufacture.
2. Description of the Prior Art
An orthesis is a device that is used to support, align or correct deformities or weaknesses in the spine, arms or legs, and to improve the function of the movable parts of the body. An Ankle Foot Orthosis (AFO) is an orthotic device for the lower limb that encloses the ankle and foot and does not extend above the knee. The Knee Ankle Foot Orthosis (KAFO) is an orthotic device for the lower limb that extends from above the knee to the ankle and foot. To correct spinal deformations, the Lumbosacral Orthosis (LSO) is a spinal orthosis that encircles the body in the lumbosacral region. There are also orthopedic devices for the upper limbs including arm, forearm, wrist, hand and thumb, as well as braces for stabilizing the neck and head.
In general, the orthopedic brace or appliance is used to: 1) control, guide, limit or immobilize and extremity, joint, or body segment; 2) restrict movement in a certain direction, or assist movement where appropriate: 3) reduce weight bearing forces on weakened joints: 4) aid rehabilitation from fractures, when casts are removed; 5) correct the shape of function of a part of the body to provide easier movement or reduce pain.
Orthopedic appliances come in all shapes and sizes and depending on the severity of the injury or deformation. Some can be purchased “as is” and strapped on the limb as a temporary brace or splint. But these generally cannot be used for correcting serious deformities or injuries which may require a “custom” fit, so that the supporting orthotic member or element conforms to the curvature of the body or limb to give maximum support.
Some orthotic devices like back braces can be made to conform to the person's anatomy, for example, the lower portion of the back by heating a relatively thick piece of thermoplastic material until pliable, then pressing into the lower lumbar region of the patient while the material is flexible. After cooling, the plastic is rigid, and can be inserted into a cloth covering that contains Velcro straps or belts to position the device against the back and supports it.
This type of “customizing” will not work for other situations, however, like spinal correction, where the orthopedic device is not simply to replicate the current condition, but rather to create a different alignment by moderate pressure on the torso by means of a customized orthotic device that creates the realignment.
The invention described below is a method of producing orthotic devices through textile braiding that are form fitting to the patients limbs and torso, but are made with high strength materials that are lighter in weight than the thick plastic materials described above and generally stronger. Like other custom orthotic products, braided products require that a solid model of the bodily part to be generated representative of the shape of that part, whether it is portions of an arm or leg, or, in the case of a spinal correction, the whole torso of the individual.
Traditionally, production of custom fit orthotic products starts with the creation of a cast of the patient's limb or torso using plaster of Paris wraps or bandages to map the shape of the bodily part. After the wrap has hardened, it is carefully removed and is used as a mold for the casting of a positive plaster mold, a replica of the body part, with a pipe embedded in the mold to facilitate handling. After the mold has set, the plaster wrap or bandage is removed.
The plaster mold or cast can be modified by the orthotics technician, known as a orthotist, by adding or subtracting material based on the orthotist's knowledge and experience of the body and its distinctive characteristics. This process of modification is referred to as rectification. The orthotist uses the cast rectification to produce a better distribution of interface pressures between the orthotic device and the limb during usage.
Alternatively, instead of casting a positive plaster replica of the limb in the hardened plaster wrap or bandage taken from the patient, some fabrication facilities create a digitized solid model computer file by scanning the inside of the patient's plaster wrap with a mechanical sensor or laser scanner. This digitized image can then be modified by computer software designed for this purpose to dimensionally add or subtract “material” from the digitized image in a manner similar to that of the technician adding or shaving material off the plaster cast to adjust or fine tune the cast to better replicate the body part.
Alternatively, a computer generated solid model can be derived from data taken directly from the surface of the limb or torso by means of various imaging devices that scan the surface of the skin and create a computerized image of the patients limb or torso. This is the preferred method of generating a computer image, hereafter referred to as the computer Solid Model, or Computer Aided Design (CAD) file of the bodily part. There is software available that can modify this CAD file electronically to “rectify” the shape as described above, adding or subtracting material digitally for a better fit, for example, by adding thickness to the model for padding or liners between the orthotic structure and the skin of the patient.
Once the CAD file is generated, it can then be loaded into computer controlled CNC machine tool often referred to as a “carver”, which cuts out a replica of the body part, plus enhancements for padding and liners, in a rigid but malleable material like a high density polymeric foam or a machine able wax. At this point, a thermoforming material can be drawn over the positive mold making a negative replica of the body part.
The next step in the conventional production process of a custom fit orthotic is to secure fabrics (graphite cloth or fiberglass weave) to the mold adding additional layers as needed depending on the required strength of the orthotic device prior to introduction of a resin matrix material to stabilize the structure of the part.
Typically, the next part of the process involves a Vacuum Assisted Resin Transfer Mold (VARTM) process where a vacuum bag is secured around the exterior of the mold containing the fiber/cloth layup and resin is introduced under a vacuum, and then manually “massaged” around the assembly to assure the cloth laminate is fully wetted. After the resin is cured, the mold is removed through scrapping out the foam, chipping out plaster, or liquefying the wax.
Some of the conventional processes suffers from a number of drawbacks. One, the wrap-casting process is somewhat messy and labor intensive as are many of the subsequent steps in the formation of orthotic product. Secondly, if the orthetist does not make a digitized solid model of the limb, there is not a permanent record of either the initial plaster wrap representing the shape of the limb, or the subsequent negative plaster mold, or, more importantly, the rectified plaster mold, since it has to be broken out the mold to complete the production of the appliance. Since there is no record of the shape of the limb or torso, the whole process has to be repeated if the orthotic product is damaged, does not fit properly or needs minor adjustments later because of weight gain or loss. The need exists for improved methods and structures for making orthotic appliances.
The invention described below is aimed at lowering the cost of conventional methods for producing custom orthotic products in a wide variety of forms and applications using textile braiding, which is rapid, repeatable, light weight, utilizing molds and mandrels based on computer-generated solid models of the patient's limbs and torso. The invention relates to the methods of manufacture where additional fixtures are added to the standard braiding machine to accommodate complex shapes like a full leg and ankle orthotic product where a standard braider/gantry machine cannot easily maneuver the mold through the braider assembly.